Geographical variation of cancer in Ireland 1995-2007


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A. Gavin1, H. Comber2, S. Deady2, N. McCluskey2, D. Donnelly1, A. Hegarty3, A-E. Carsin4
1Northern Ireland Cancer Registry, Belfast, UK, 2National Cancer Registry Ireland, Cork, Ireland, 3University of Limerick, Limerick, Ireland, CREALCentre for Research in Environmental Epidemiology

Background

The Island of Ireland (5 million) has two different health services, a range of urban and rural settlements and different socio-economic groups. Cooperation between the two population based cancer registries NCRI and NICR have identified areas for research and service change.

Method

Incidence data on almost 347,000 cancers diagnosed in the island of Ireland 1995-2007 inclusive were combined at the smallest geographical level and analysed by negative binomial regression of incidence rates using population density, percentage unemployed and educational level to examine relationship to cancer risk for the Republic of Ireland (RoI) and Northern Ireland (NI). Smoothed incidence data were mapped to demonstrate geographical patterns in cancer relative risk for 18 of the most common cancers.

Results

Risk for many cancers was higher in RoI eg non-melanoma skin cancer, melanoma, leukaemia, bladder, pancreas and brain/CNS for both sexes, prostate in men, oesophagus and cervix in women. In NI, lung cancer risk was higher for both sexes, and among women risk was higher for non Hodgkin lymphoma, head and neck and cancer of uterus. Patterns consistent with known socio-economic gradients were seen with higher risk in urban areas.

Conclusion

Patterns reflected (i) socio-economic deprivation eg tobacco related cancers (ii) service organisation related to different health care systems eg prostate cancer (iii) patterns linked with lifestyle eg non-melanoma skin cancer around the coast (iv) unexplained patterns for stomach and colorectal cancers.